Generally, insufflation gas is conditioned i.e. heated and hydrated in apparatuses that are located upstream of the trocar. There are advantages to having the gas conditioning apparatus upstream of the trocar including the ability to isolate the hydration apparatus from the trocar thereby allowing one to maintain a small profile trocar for ease in handling and manipulating by a surgeon. A further benefit or upstream conditioning is that if the insufflation gas should be accidentally overheated the mass of the trocar and the mass of the connecting tubing and fittings tend to absorb excess heat thereby acting as a thermal sink to limit the temperature of the gas before it enters a patient, which reduces the chances that overheated insufflation gas may enter the patient. However, a benefit of the gas conditioning trocar is that the insufflation gas can be heated and hydrated immediately before entering a patient thus minimizing cooling of the heated insufflation gas during the enter into the patient. The source of conditioned gas closer to the patient also permits more accurate control of the temperature and humidity of the insufflation gas as it enters the body cavity since the opportunity for gas cooling is minimized. The minimizing of cooling of the insufflation gas also minimizes or eliminates a problem of moisture condensation in the insufflation gas, which may occur as a result of the insufflation gas cooling on its path into the body cavity of a patient. However in either case the temperature of the insufflation gas is typically maintained by a feedback system that measures the temperature of the gas and adjusts the heat input based on the existing temperature.
The location of the heating and hydration of the insufflation gas either within a trocar or proximate a trocar minimizes problems of condensation and gas cooling. However, other trocar operating concerns may arise since the heating and hydration control of the insufflation gas may occur in close proximity to the patient and in some cases immediately after the insufflation gas has been heated and hydrated. In some cases a failure of the temperature control system may lead to overheated insufflation gas being injected into a patient.